Hyperkinetic Movement Disorders in Children: A Brief Review

Movement disorders are common neurologic disturbances in childhood. There are two major types of movement disorders. Hypokinetic disorders are with paucity of voluntary movements and are very uncommon in pediatric age group. Hyperkinetic movement abnormalities are very common in children and defined as abnormal repetitive involuntary movements. Movement disorders in childhood and even in adolescents are different in etiology, timing, treatment and prognosis versus adulthood movement abnormalities. In this brief article, we reviewed common types of hyperkinetic abnormal movements in children and adolescents with emphasis on etiologies, new classifications and recent treatment strategies.

On the contrary, hypokinetic movement disorders revealed with reduced voluntary movements and akinesia (3,4). Hypokinetic movement disorders are very unusual in pediatrics, therefore, in this review article, we dealt with some common hyperkinetic movement disorders in children with emphasis on etiologies, update classifications and new aspects of treatment.

Definition
Irregular, random, chaotic, brief and purposeless movements may flow from one part of body to another (5). These movements cannot be suppressed voluntarily (5,6). Although most children with chorea have history of brain injuries but rare genetic causes should be considered (6). Athetosis is slower and writhing form of chorea with involvement of distal part of extremities more than proximal. Conversely, Ballismus is high-amplitude, forceful and flinging form of chorea that mainly involves proximal joints and muscles (5)(6)(7). Pathophysiologically, chorea typically occurs due to dysfunction of the striatum or subthalamic nucleus (1,5) (Figure 1).

Definition
Tremor is defined as oscillatory, involuntary, regular, and rhythmic movements of body parts.
Tremor can affect head, extremities, trunk and even soft palate separately or combined (25,26).

General aspects
Nowadays, treatment of movement disorders should be performed based on the symptomatology independent of underlying condition (2,4). In fact, we want to disrupt the connection between pathophysiological cause and clinical presentation on basis of neurotransmitters' functions. On the other hand, we have to try to reduce personal/ social disabilities due to abnormal movements with pharmacologic with or without supportive therapy (2,4,13). Moreover, we should recognize the main etiology of abnormal movement and other underlying conditions for decision of the best treatment strategy.  (32,33). Deep brain stimulation (DBS) can be used in refractory cases (30,33).
-Dystonia: Some common forms of primary dystonia are dopa-responsive and starting a trial of L-DOPA for all children with unexplained dystonia is reasonable (4,13,34). Anticholinergic drugs are effective in many types of dystonia (2,13,34).
Recently, octanoic acid has been used for severe essential voice tremors (43).